Share your knowledge on these two classic MPCs
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By Scheme Mon Mar 09, 2015 2:27 am
Hey everyone it's been a long while since I've been here. :-D
So I just got the bug to buy a new foil for my display since this unit has been sitting on a shelf for close to 10 years. So I installed the purchased display and it lights up the screen but.... I cannot see any text on the screen when the contrast knob is turned. I tried searching through the forum and couldnt find any information on text not being displayed on a lit (visible) display.
Does anyone have any clue as to what this might be?

Another question while I'm here, I know that the MPC 3000 had/has an optional VGA display part. Does anyone know if something like this exists for the MPC 60 MK2?
I figure if that was an option I could bypass the internal display and just use an external one.
Thanks in advance everyone!
User avatar
By mr_debauch Mon Mar 09, 2015 6:11 am
no VGA adapter for the 60..

but for the other thing... the standard thing to try and do is open up the machine and unplug all cables and connectors... then reconnect them to make sure they didn't wiggle loose over the years with expansion and contraction etc.. sometimes that happens and you lose thing like display.

try it out just in case... if that doesn't help.. maybe one of the engineer types around here might be able to really help you.
User avatar
By Scheme Mon Mar 09, 2015 7:34 am
Thanks mr_debauch... after some tinkering I think I may have narrowed down the issue.
Here's a recap...
After fooling around with this MPC 60 MK II that I had on the shelf for like 13 years I decided to work on the display. Got the replacement LED foil and it lit up after some cleaning. But when I went to adjust the contrast it didn't do anything although it was lit. Well, after checking some schematics and testing out some connections and using a multimeter, I've come to the loose conclusion that I have a bad resistor probably caused by a backwards installed wire.
I don't know this for sure but, I do think I'm very close to solving this. If anyone here is familiar with schematics and resistors blah blah blah, let me know what you think. I've never really done this before so I'm just trying to take my best educated guess.
The resistor in question in the R69 that's near the power supply clip that is supposed to be connected to contrast knob and the LCD display (those are P209 & P205).
Note* The schematic of the PCB is actually inverted and looks upside down/backwards.
So made it green and I inverted the PCB and numbers for the areas I'm speaking on so they are seen as they are on the PCB itself.
:hmmm:

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MPC 60 MK II PCB (schematic is inverted and upside down)

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PCB resistor in question is the one marke R69 (aqua with legs)

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This is the correct view of the PCB with the numbers I mentioned in the correct places. (R69-P209-P205)

If anyone has any input it would be highly appreciated :worthy:
User avatar
By Scheme Mon Mar 09, 2015 7:35 pm
A pair of Glasses wrote:If u don't thrust r69, solder it out and measure it.
U can tell its value by the colored rings on it.
Greets



Yes that's exactly what I'm going to do :nod:
User avatar
By Scheme Mon Mar 09, 2015 11:33 pm
So I'm trying to figure out the resistor values, OHM info and anything else I'd need so I can get the correct part.
But I'm having a problem because I'm trying to use a resistor calculator and I'm partially color blind. I cannot figure out what the colors to this R69 resistor are.
Any suggestions?
:WTF:

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By MPCHunter Tue Mar 10, 2015 1:51 am
Scheme wrote:So I'm trying to figure out the resistor values, OHM info and anything else I'd need so I can get the correct part.
But I'm having a problem because I'm trying to use a resistor calculator and I'm partially color blind. I cannot figure out what the colors to this R69 resistor are.
Any suggestions?
:WTF:



It is a 330 Ohm resistor which acts as a fuse in the circuit.
User avatar
By Scheme Tue Mar 10, 2015 2:56 am
MPCHunter wrote:
Scheme wrote:So I'm trying to figure out the resistor values, OHM info and anything else I'd need so I can get the correct part.
But I'm having a problem because I'm trying to use a resistor calculator and I'm partially color blind. I cannot figure out what the colors to this R69 resistor are.
Any suggestions?
:WTF:



It is a 330 Ohm resistor which acts as a fuse in the circuit.


Thank you MPC Hunter!

I finally figured out I was reading the resistor colors in reverse due to the inverted schematic I found online. It finally did show up at 33 ohms.

is there another value I need to know or is that all I need? Just ask for a 330 ohm resistor at radio shack? Wattage? 10% %5? Do colors matter?
:hmmm:
Sorry as I stated before I'm very new (green) to this.

Thanks again for all the feedback, it's highly appreciated.
By MPCHunter Tue Mar 10, 2015 3:49 am
Yes you are right it is 33 Ohms, not 330 as I typed earlier... my bad.

1/4W resistor. 1% or 5% tolerance doesn't matter. Try to find a resistor close to the 33 Ohm value if you can. It's there to protect the LCD so the further you go away from 33 Ohms the more damage could theoretically happen.

You do not necessarily need a green colored one(the green designates that the resistor is flame proof). The green resistors do not produce as much "magic smoke" when they blow compared to regular carbon/metal film resistors.

If your local radio shack doesn't have one in stock, try calling around to a local electronics repair place and they might have one for you
User avatar
By Scheme Tue Mar 10, 2015 4:10 am
MPCHunter wrote:Yes you are right it is 33 Ohms, not 330 as I typed earlier... my bad.

1/4W resistor. 1% or 5% tolerance doesn't matter. Try to find a resistor close to the 33 Ohm value if you can. It's there to protect the LCD so the further you go away from 33 Ohms the more damage could theoretically happen.

You do not necessarily need a green colored one(the green designates that the resistor is flame proof). The green resistors do not produce as much "magic smoke" when they blow compared to regular carbon/metal film resistors.

If your local radio shack doesn't have one in stock, try calling around to a local electronics repair place and they might have one for you



Once again MPC Hunter this is very much appreciated! :worthy:
User avatar
By Scheme Fri Mar 13, 2015 6:45 pm
The schematic I was reading from is inverted and upside down, I changed it to read as the one of my board. Apparently it's Orange, Orange, Black, Red, Gold/Silver.
The resistor should be read from right to left, but in the photo it is left to right.
I was reading the numbers printed on the PCB and was confused about how to input them into a resistor calc. After the flip (orange to silver/gold) the OHM reading was 33 OHMS and read correctly. I have not yet installed it, but I picked up a 33 OHM resistor that is a 1/2 watt with a 5% tolerance. I hope this will be correct. :hmmm:


A pair of Glasses wrote:Correct me if iam wrong, but the resistor in the picture, goes from the right to left?
And than red,red,black,purple,silver??
Don't have the schematics on this one, but am I seeing this right?

Greets